β-butyrolactone

Structural formula
Simplified structural formula without stereochemistry
General
Surname	β-butyrolactone
other names	4-methyl-2-oxetanone ( IUPAC ) beta-butyrolactone 4-methyl-2-oxetanone 3-methylpropiolactone β-methyl-β-propiolactone 3-hydroxybutyric acid-β-lactone β-BL ( RS ) -BBL
Molecular formula	C 4 H 6 O 2
Brief description	colorless to light yellow liquid
External identifiers / databases
CAS number 3068-88-0 EC number 221-330-3 ECHA InfoCard 100.019.392 PubChem 18303 ChemSpider 17288 Wikidata Q27155863
properties
Molar mass	86.09 g mol −1
Physical state	liquid
density	1.056 g cm −3 at 25 ° C
Melting point	−43.5 ° C −44 ° C
boiling point	71-73 ° C at 39 h Pa 87 ° C at 6.7 k Pa
Vapor pressure	220 Pa (20 ° C)
solubility	soluble in water (268 g l −1 at 25 ° C) soluble in numerous organic solvents
Refractive index	1.4100-1.420 (20 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 226-315-319-351 P: 281-305 + 351 + 338
Toxicological data	17,200 µl kg −1 ( LD 50 ,  rat ,  oral ) > 20 ml kg −1 ( LD 50 ,  rabbit ,  transdermal )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

β-Butyrolactone is the intramolecular carboxylic acid ester ( lactone ) of the optically active 3-hydroxybutanoic acid and is obtained as a racemate during chemical synthesis . 3-Hydroxybutyric acid-β-lactone is suitable as a monomer for the production of the biodegradable polyhydroxyalkanoate poly (3-hydroxybutyrate) (PHB). Polymerization of racemic ( RS ) -4-methyl-2-oxetanone gives ( RS ) - polyhydroxybutyric acid , which, however, has essential properties, e.g. B. strength or degradation behavior , the bacterial reserve material ( R ) -Poly-3-hydroxybutyrate derived from natural sources is inferior.

Occurrence and representation

The addition of acetaldehyde to ketene in the presence of the clay mineral montmorillonite gives β-butyrolactone in 63% yield.

The intermediate ketene formed by the dehydrobromination of acetyl bromide with the Hünig base diisopropylethylamine reacts enantioselectively in the presence of a chiral aluminum complex to form ( S ) -β-butyrolactone in 92% yield with an enantiomeric excess ee of over 98%.

Hydrogenation of diketene on a palladium contact gives β-butyrolactone in 93% yield.

The asymmetric hydrogenation of diketene with a ruthenium - BINAP catalyst to optically active ( R ) - 4-methyl-oxetan-2-one with 97% selectivity and 92% enantiomeric excess is also described.

With the homogeneous carbonylation catalyst [(salph) Al (THF) ₂ ] [Co (CO) ₄ ] according to Geoffrey Coates, which is accessible from a modified aluminum- salen complex [(salph) AlCl and sodium tetracarbonylcobaltate NaCo (CO) ₄ ] , at 50 ° C and about 60 bar CO pressure ( R ) - propylene oxide carbonylated to ( R ) -BBL with retention of the configuration in 95% yield .

The carbonylation of 1,2-epoxypropane in the presence of homogeneous porphyrin carbonyl cobaltate catalysts in tetrahydrofuran is successful even at a carbon monoxide partial pressure of about 14 bar and gives 3-methylpropiolactone in 97% yield.

Because of the problems with the separation and recycling of homogeneous carbonylation catalysts, heterogeneous polymer analogues have recently been worked on, which give similarly high yields (up to 96%) at 60 bar CO pressure, but with drastically lower catalytic activity in 50mmolar laboratory batches, they are not yet promising candidates appear for an industrial application.

The inexpensive starting material 1,3-butanediol can be converted into β-butyrolactone (74% yield) within 1 hour with the oxidizing agent barium manganate BaMnO ₄ in acetonitrile under microwave irradiation .

properties

β-Butyrolactone is an acetone-like or mint-smelling clear liquid that mixes with water and is soluble in many organic solvents. According to a classification by the IARC , β-butyrolactone is assigned to group 2B: “possibly carcinogenic ”.

Applications

( R ) -β-Butyrolactone reacts in toluene solution at approx. 14 bar CO pressure and 55 ° C in the presence of a salen complex within 24 h with inversion of the configuration in 94% yield to give optically pure (> 99% ee ) ( S ) -methyl succinic anhydride.

Homo- and copolymers from β-butyrolactone

The commercialization of the polyhydroxybutyric acid PHB isolated from bacteria or the homo- and copolymeric polyhydroxyalkanoates as aerobically biodegradable thermoplastics under the brand name Biopol® by Imperial Chemical Industries ICI in 1983 set the starting point for the search for synthetic alternatives, the disadvantages of PHB such as brittleness and rigidity, should avoid thermal decomposition even at temperatures just above the melting temperature (175-180 ° C) and especially uncompetitive costs due to expensive fermentation, isolation and purification.

The ring-opening polymerization of ( S ) -β-butyrolactone with diethylzinc ZnEt ₂ / water produces poly ( S ) -3-hydroxybutyrate with ee > 97% with retention of the configuration at the chiral carbon atom .

With tin compounds (distannoxanes) as catalysts, high molecular weight (M _n > 100,000) synthetic ( R ) -polyhydroxybutyrates, which are similar to natural polyhydroxyalkanoates, are formed in the polymerization of ( R ) -β-BL, also with retention .

The anionic polymerization of optically active β-butyrolactone leads under inversion to crystalline, isotactic polyhydroxybutyrates, the low polydispersity M _w / M _n ≈ 1.2 indicates the presence of a living polymerization.

Even very strong bases, such as B. diazabicycloundecene DBU, 1,5,7-triazabicyclo (4.4.0) dec-5-ene TBD and the phosphazene BEMP are capable of ring-opening polymerization of β-butyrolactone in substance at 60 ° C to low molecular weight (M _n <21,000 ) To catalyze PHBs with narrow molecular weight distribution.

The cationic ring-opening polymerization of β-butyrolactone with very strong acids, such as. B. trifluoromethanesulfonic acid leads to low molecular weight PHBs (M _n <8,200) with living hydroxy chain ends to which z. B. Caprolactone blocks can be polymerized.

With yttrium- based catalysts, racemic β-butyrolactone can be converted into (predominantly) syndiotactic PHB with a narrow molar mass distribution.

N-heterocyclic carbenes (NHCs) of the imidazol-2-ylidene type are strong nucleophiles and are also suitable as initiators for the ring-opening polymerization of lactones such as β-butyrolactone.

Synthetic PHB variants, which were developed as homopolymers of β-butyrolactone or copolymers with other lactones, have so far not been able to compensate for the weaknesses of the biogenic material - in particular, unfavorable mechanical and thermal properties and high price. Instead, there were new problems with toxic heavy metals in the catalysts (e.g. tin, cobalt or chromium ) and atactic (liquid and difficult to separate) polymer components with undesirable material properties. Even more than 30 years after its market launch, the economic success of the biopolymer Biopol® and its (bio) synthetic analogues is modest, and despite ambitious capacity targets (actual global polyhydroxyalkanoate PHA capacity 2018: approx. 30,000 tons) , their sales are far below the optimistic ones Manufacturers' forecasts lagged behind.

Individual evidence

1. ↑ ^{a b c d e f g h i j} Entry on β-butyrolactones at TCI Europe, accessed on December 20, 2018.
2. ↑ ^{a b c d e} data sheet β-butyrolactone from Sigma-Aldrich , accessed on December 20, 2018 ( PDF ).
3. ↑ H. Abe, I. Matsubara, Y. Doi, Y. Hori, A. Yamaguchi: Physical properties and enzymatic degradability of poly (3-hydroxybutyrate) stereoisomers with different stereoregularities . In: Macromolecules . tape 27 , no. 21 , 1994, p. 6018-6025 , doi : 10.1021 / ma00099a013 .
4. ↑ Patent US2580714 : Production of beta-hydroxy carboxylic acid lactones from ketene and aldehyde with clay catalyst. Filed May 24, 1949 , published January 1, 1952 , Applicant: Union Carbide and Carbon Corp., Inventor: FG Young, JT Fitzpatrick. ‌
5. ↑ SG Nelson, WS Cheung, AJ Kassick, MA Hilfiker: A de novo enantioselective total synthesis of (-) - laulimalide . In: J. Amer. Chem. Soc. tape 124 , no. 46 , 2002, p. 13654-13655 , doi : 10.1021 / ja028019k .
6. ↑ Patent US2763664 : Process for manufacturing β-butyrolactone from diketene. Registered on December 6, 1952 , published on September 18, 1956 , applicant: Wacker-Chemie GmbH, inventor: J. Sixt. ‌
7. ↑ T. Ohta, T. Miyake, H. Takaya: An efficient synthesis of optically active 4-methyloxetan-2-one: asymmetric hydrogenation of diketene catalysed by binap-ruthenium (II) complexes [binap = 2,2′-bis ( diphenylphosphino) -1,1'-binaphthyl] . In: J. Chem. Soc., Chem. Commun. tape 0 , no. 23 , 1992, pp. 1725-1726 , doi : 10.1039 / C39920001725 .
8. ^ Catalysts for Carbonylation. In: Aldrich ChemFiles 2007, 7.5, 3. Sigma Aldrich, 2007, accessed on December 20, 2018 . 
9. ↑ YDYL Getzler, V. Mahadevan, EB Lobkovsky, GW Coates: Synthesis of β-lactones: a highly active and selective catalyst for epoxide carbonylation . In: J. Amer. Chem. Soc. tape 124 , no. 7 , 2002, p. 1174–1175 , doi : 10.1021 / ja017434u .
10. ↑ Patent US2012123137A1 : Process for beta-lactone production. Filed April 7, 2010 , published May 17, 2012 , Applicant: Novomer, Inc., Inventors: SD Allen, RR Valente, H. Lee, AE Cherian, DL Bunning, NA Clinton, OS Fruchey, BD Dombek. ‌
11. ↑ J. Jiang, S. Yoon: A metalated porous porphyrin polymer with [Co (CO) ₄ ] ^- anion as an efficient heterogeneous catalyst for ring expanding carbonylation . In: Nature Scientific Reports . tape 8 , no. 13243 , 2018, p. 1-6 , doi : 10.1038 / s41598-018-31475-6 .
12. ↑ MC Bagley, Z. Lin, DJ Phillips, AE Graham: Barium manganate in microwave-assisted oxidation reactions: synthesis of lactones by oxidative cyclization reactions . In: Tetrahedron Lett. tape 50 , no. 49 , 2009, p. 6823-6825 , doi : 10.1016 / j.tetlet.2009.09.117 .
13. ↑ YDYL Getzler, V. Kundnani, EB Lobkovsky, GW Coates: Catalytic Carbonylation of β-lactones to succinic anhydrides . In: J. Amer. Chem. Soc. tape 126 , no. 22 , 2004, p. 6842-6843 , doi : 10.1021 / ja048946m .
14. ↑ ICI reduces cost, ups capacity for Biopoly. ICIS, September 22, 1991, accessed December 20, 2018 . 
15. ^ Y. Zhang, RA Gross, RW Lenz: Stereochemistry of the ring-opening polymerization of ( S ) -β-butyrolactone . In: Macromolecules . tape 23 , no. 13 , 1990, pp. 3206-3212 , doi : 10.1021 / ma00215a002 .
16. Jump up ↑ Y. Hori, M. Suzuki, A. Yamaguchi, T. Nishishita: Ring-opening polymerization of optically active β-butyrolactone using distannoxane catalysts: Synthesis of high molecular weight poly (3-hydroxybutyrate) . In: Macromolecules . tape 26 , no. 20 , 1993, p. 5533-5534 , doi : 10.1021 / ma00072a037 .
17. ↑ Z. Jedlinski, P. Kurcok: First facile synthesis of biomimetic poly ( R ) -3-hydroxybutyrate via regioselective anionic polymerization of ( S ) -β-butyrolactone . In: Macromolecules . tape 31 , no. 19 , 1998, pp. 6718-6720 , doi : 10.1021 / ma980663p .
18. ↑ R. Kurcak, M. Smiga, Z. Jedlinski: β-butyrolactone polymerization initiated with tetrabutylammonium carboxylates: a novel approach to biomimetic polyester synthesis . In: J. Polym. Sci .: Part A: Polym. Chem. Band 40 , no. 13 , 2002, p. 2184-2189 , doi : 10.1002 / pola.10285 .
19. ↑ CG Jaffredo, J.-F. Carpentier, SM Guillaume: Controlled ROP of β-butyrolactone simply mediated by amidine, guanidine, and phophazene organocatalysts . In: Macromol. Rapid Comun. tape 33 , no. 22 , 2012, p. 1938–1944 , doi : 10.1002 / marc.201200410 .
20. ↑ A. Couffin, B. Martin-Vaca, D. Bourissou, C. Navarro: Selective O-acyl ring-opening of β-butyrolactone catalyzed by TRIFLUOROMETHANE sulfonic acid: application to the preparation of well-defined block copolymer . In: Polym. Chem. Band 5 , no. 1 , 2014, p. 161-168 , doi : 10.1039 / C3PY00935A .
21. ↑ A. Amgoune, CM Thomas, S. Ilinca, T. Roisnel, J.-F. Carpentier: Highly active, productive, and syndiospecific yttrium initiators for the polymerization of racemic β-butyrolactone . In: Angew. Chem. Int. Ed. tape 45 , no. 17 , 2006, p. 2782–2784 , doi : 10.1002 / anie.200600058 .
22. ↑ J.-F. Carpentier: Discrete metal catalysts for stereoselective ring-opening polymerization of chiral racemic β-lactones . In: Macromol. Rapid Commun. tape 31 , no. 19 , 2010, p. 1696-1705 , doi : 10.1002 / marc.201000114 .
23. ↑ WN Ottou, H. Sardon, D. Mecerryes, J. Vignolle, D. Taton: Update and challenges in organo-mediated polymerization reactions . In: Progress in Polymer Science . tape 56 , 2016, p. 64-115 , doi : 10.1016 / j.progpolymsci.2015.12.001 .
24. ↑ Bioplastic market data , accessed December 20, 2018.